The invention relates to a coating apparatus of an airbag reinforcing liquid which coats a sewn part of an airbag with a reinforcing liquid.
In an airbag formed by sewing a plurality of pieces of cloth, there is a concern that, when the airbag is spread and inflated by an inflation gas, the cloth is stretched, and an excessive load is applied to the sewn part, resulting in causing a misalignment. The misalignment indicates that an initial shape is collapsed which should be originally maintained due to mutual restraint of a warp and a weft in the cloth, and a weave pattern is misaligned to impair an appearance. Further, there is a concern that the misalignment is enlarged due to a high pressure inflation gas flowing through the seam of the sewn part with high temperature.
In this regard, the sewn part is reinforced. As a mode of the reinforcement, it is common to coal a surface of the cloth coming in touch with the inflation gas with silicone and the like, and to sew a ribbon-shaped (belt-shaped) reinforcing cloth over the cloth.
However, even in the mode of the reinforcement, the bulk of the airbag housed in a folded-up state is increased. In order to suppress the enlargement of the misalignment while suppressing the increase of the bulk, therefore, a technique has been considered in which only the sewn part and the peripheral portion are coated with a reinforcing liquid. For example, a sewing machine is disclosed in JP-A-2004-60071 in which a chuck, which can perform coating along the seam in conjunction with the movement of the sewing needle, is provided, and a chalk-shaped solid body for coating is fixed to the chuck (for example, see FIG. 6).
Incidentally, in the above-described technique in the related art, the chuck is moved separately from the sewing needle so that a dedicated mechanism which is in conjunction with the movement of the sewing needle is needed additionally. Thus, the coating apparatus becomes complicated, which is problematic.